nodemcu-firmware/lua_modules/liquidcrystal/lc-gpio8bit.lua

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2020-04-18 16:35:14 +02:00
local gpio, bit = gpio, bit
return function(bus_args)
local rs = bus_args.rs or 0
local rw = bus_args.rw
local en = bus_args.en or 1
local bl = bus_args.backlight
local d0 = bus_args.d0 or 2
local d1 = bus_args.d1 or 3
local d2 = bus_args.d2 or 4
local d3 = bus_args.d3 or 5
local d4 = bus_args.d4 or 6
local d5 = bus_args.d5 or 7
local d6 = bus_args.d6 or 8
local d7 = bus_args.d7 or 9
for _, d in pairs({rs,rw,en,bl}) do
if d then
gpio.mode(d, gpio.OUTPUT)
end
end
local function setGPIO(mode)
for _, d in pairs({d0, d1, d2, d3, d4, d5, d6, d7}) do
gpio.mode(d, mode)
end
end
setGPIO(gpio.OUTPUT)
local function send8bitGPIO(value, rs_en, rw_en, read)
local function exchange(data)
local rv = 0
if rs then gpio.write(rs, rs_en and gpio.HIGH or gpio.LOW) end
if rw then gpio.write(rw, rw_en and gpio.HIGH or gpio.LOW) end
gpio.write(en, gpio.HIGH)
for i, d in ipairs({d0, d1, d2, d3, d4, d5, d6, d7}) do
if read and rw then
if gpio.read(d) == 1 then rv = bit.set(rv, i-1) end
else
gpio.write(d, bit.isset(data, i-1) and gpio.HIGH or gpio.LOW)
end
end
gpio.write(en, gpio.LOW)
return rv
end
if read then setGPIO(gpio.INPUT) end
value = exchange(value)
if read then setGPIO(gpio.OUTPUT) end
return value
end
-- Return backend object
return {
fourbits = false,
command = function (screen, cmd)
return send8bitGPIO(cmd, false, false, false)
end,
busy = function(screen)
if rw == nil then return false end
return bit.isset(send8bitGPIO(0xff, false, true, true), 7)
end,
position = function(screen)
if rw == nil then return 0 end
return bit.clear(send8bitGPIO(0xff, false, true, true), 7)
end,
write = function(screen, value)
return send8bitGPIO(value, true, false, false)
end,
read = function(screen)
if rw == nil then return nil end
return send8bitGPIO(0xff, true, true, true)
end,
backlight = function(screen, on)
if (bl) then gpio.write(bl, on and gpio.HIGH or gpio.LOW) end
return on
end,
}
end